From DSNewsThere were 1.7 million REOs and homes facing imminent foreclosure that had not yet hit the market at the end of the third quarter, according to data released Thursday by First American CoreLogic.

The company says that at the current sales pace, it would take 3.3 months to get rid of this looming “shadow inventory.” By comparison, First American CoreLogic says shadow inventory a year ago was 1.1 million, representing a 2.4 month backlog.

Shadow inventory is not included in official measures of unsold inventory. According to First American CoreLogic’s

analysis, the visible supply of unsold inventory – accounting for new and existing homes that are currently on the market – was 3.8 million units in at the end of September, down from 4.7 million a year earlier. The visible months’ supply fell to 7.8 months in September 2009, down from 10.1 months a year earlier.

Together, total inventory of unseen and marketed properties comes to 5.5 million units as of September 2009, an 11.1 months’ supply of homes. That figure is down from a total inventory of 5.7 million a year ago, which equates to a 12.7 months backlog.

First American CoreLogic says this indicates that while the visible months’ supply has decreased and is beginning to approach more normal levels, adding in the pending supply reveals there is still quite a bit of inventory that will impact the housing market for the next few years.

Just how big of an impact the shadow inventory makes will depend on whether it hits the market in large fell swoops or makes its way out of the darkness in steady, manageable streams. According to a new report from Radar Logic, the looming distressed property supply will enter the housing market at a controlled rate that can be absorbed by existing demand without drastically reducing prices